The present invention relates to improving the success of satellite personal communications network (S-PCN) services, such as paging and call-notification, especially in dense urban areas. More specifically, the present invention relates to a method and apparatus for permitting user terminals (UT's) to transmit and respond to requests for co-operative forwarding of pages or rings. These UT's may be, for example, a pager or telephone.
S-PCN services utilize geostationary or non-geostationary orbit satellites to transmit messages. The transmitted messages are received by UT's which generally decode the message and alert the user to the receipt of the message. A transmitted message is usually a brief sequence of data which generally includes the unique address of the intended UT followed by alpha-numeric information. When the UT is a pager, this information may be, for example, a number to call, an agreed code, or a short sentence. When the UT is a telephone, this information may be, for example, an instruction to activate the UT's ringer. Current satellite power limitations, however, prevent the transmission of signals of sufficient strength to ensure penetration into ferro-concrete-glass buildings. These buildings, however, house a very important customer group for S-PCN services. Further, this customer group must be served with high dependability to ensure the success of the S-PCN service.
Therefore, a system must be developed to permit high dependability messaging into such an environment. One alternative would be to place high-power paging and ringing repeaters into selected high-density cities. However, in addition to its own technical drawbacks, this alternative would produce a negative image for a global satellite system. Although traditionally pagers are one-way devices, another alternative would present a two-way UT for messaging. However, this alternative is impractical because of battery-power limitations, as messages would be required to reach back to the satellite. It would therefore be desirable to utilize some form of two-way paging, without the need to send messages back to the satellite.